The effect of phosphate binder therapy with sucroferric oxyhydroxide on calcification propensity in chronic haemodialysis patients: a randomized, controlled, crossover trial

Background Calcification propensity is associated with the risk for cardiovascular events and death in end-stage renal disease patients. Here we investigated the effect of lowering serum phosphate with oral phosphate binder therapy on calcification propensity. Methods We performed an open-label, randomized, controlled, crossover study in chronic haemodialysis patients with hyperphosphataemia. Patients (n = 39) were randomized in a 1:1 ratio to either low-dose (250 mg/day) sucroferric oxyhydroxide (SO) followed by high-dose (2000 mg/day) SO or vice versa, with washout phases before and after SO treatment. The primary endpoint was changed in calcification propensity as measured by calciprotein particle formation time (T50 test) between washout and high-dose SO treatment in patients with ≥85% adherence to the prescribed SO dose (per-protocol analysis). Results In the primary per-protocol analysis (n = 28), 2000 mg/day SO treatment resulted in a mean increase in T50 of 66 min (95% CI 49–84 min, P < 0.0001), from 243 ± 63 to 309 ± 74 min compared with phosphate binder washout. Serum phosphate decreased from 2.28 ± 0.5 to 1.63 ± 0.43 mmol/L (P < 0.0001). SO at 250 mg/day did not influence T50 (P = 0.4) or serum phosphate concentrations (P = 0.9) compared with phosphate binder washout. The secondary intention-to-treat analysis (n = 39) showed similar results: an increase in T50 of 52 min (95% CI 31–74 min, P < 0.0001) and a decrease in serum phosphate from 2.18 ± 0.5 to 1.64 ± 0.46 mmol/L. No major adverse cardiovascular event, case of calciphylaxis or death occurred during the study. Conclusion Phosphate binder treatment with SO improves serum calcification propensity of haemodialysis patients and might lead to improved outcomes.